Given that this machine may very well be the single most reliable motorcycle that has ever been built, I'd say it's not worth it.
I had the 5 year plan on my Yamaha 242 LS boat, because it came free for a boat show special, but we never needed it.
Never needed a repair on my Rhino 700 either.
Or my TTR125.
or my TTR90.
Or the two XT225's before that.
Or the Rhino 660 before that.
Hmmm, I'm seeing a pattern here...